Sonography of small renal masses with indeterminant density characteristics on computed tomography

Abstract

Nine small renal masses with attenuation coefficients greater than 20 HU on computed tomography (CT) were termed indeterminate for cyst or renal cell carcinoma. Correlative sonography identified the fluid-filled internal architecture in four of five cysts and correctly characterized as solid four small renal cell carcinomas. The sonogram was particularly valuable in assessing masses that were indeterminate on CT when enhancement was equivocal or when intravenous contrast could not be administered. We conclude that sonography is extremely useful as a noninvasive procedure in evaluating the occasional small renal mass with CT number greater than 20 HU.

Enhancement patterns of renal masses during multiphase helical CT acquisitions

“…The expected pattern of enhancement of RCC during the cortical nephrographic phase, in keeping with the reported frequent hypervascularity of RCC, should be one of hyperattenuation [2,4,5,11,27]. This hypervascular appearance of RCC, mostly reported in the angiographic literature, is described in at least 80% of RCC.…”

Radiologic Evaluation of Small Renal Masses (I): Pretreatment Management

“…Sonography is very accurate in distinguishing liquid from solid tissue. Therefore, its major use in these small lesions is to help differentiate small cysts (see Figure 1) from small solid tumors [8]. Maintaining rigid criteria is necessary to maintain the high accuracy possible with this technique.…”

Optimal Management of Small Renal Masses

“…Other findings, such as internal echoes, mural nodules, or lack of distal acoustic enhancement, are more likely seen in neoplasms. 13 Computed tomography (CT) is becoming the most common modality used to diagnose renal masses. Significant contrast enhancement correlates with renal neoplasm.…”

“…Small increases in attenuation may be caused by partial volume averaging. 13 Other CT criteria suggestive of malignancy include central calcification, marginal irregularity, and inhomogeneity. 14 These characteristics may be difficult to identify in masses smaller than 1 cm, and therefore serial CT may be better.…”